1. Technical Field
The present invention relates to an electroluminescent device, and specifically to an electroluminescent device using an inorganic phosphor material.
2. Description of the Related Art
In recent years, electroluminescent devices (hereinafter, referred to as an EL device) receive attention as a surface-emitting device of a light weight and a low-profile. The EL devices are broadly divided into an organic EL device using an organic phosphor material as a phosphor material and an inorganic EL device using an inorganic phosphor material as a phosphor material. Among others, dispersion type inorganic EL devices (hereinafter, referred to as a dispersion type EL device), in which a phosphor layer is formed by a screen printing method or the like using a phosphor material paste, receive attention since they have advantages that power consumption is low and further a manufacturing cost is low because of easy manufacturing. The dispersion type EL devices, however, had a problem that they cannot be applied to displays such as a television set requiring high luminance due to low luminance brightness.
And so, there have been proposed various approaches in order to resolve this issue. For example, in Japanese Patent Laid-open Publication No. 2001-185358, there is disclosed a dispersion type EL device in which higher luminance is realized by increasing a voltage applied to a phosphor layer by enhancing a dielectric constant of a layer of a phosphor material using a phosphor material coated with PbTiO3.